Cleansing compositions

ABSTRACT

A denture cleansing composition comprising an inorganic persalt bleaching agent, an effervescence generator and an aminoalkysilicone. The composition provides improved antiplaque, cleasing and antibacterial activity together with excellent physical and in-use performance characteristics.

TECHNICAL FIELD

The present invention relates to cleansing compositions and especiallyto compositions for use in cleansing dentures and the like. Inparticular, the invention relates to denture cleansing compositionshaving enhanced antiplaque activity together with excellent denturecleansing performance, appearance, physical and dissolutioncharacteristics, anti-bacterial efficacy and in-use performancecharacteristics.

BACKGROUND

Effervescent tablets and powders for cleansing dentures and the like arewell known in the art. The aim of a denture cleanser product is to cleanthe denture as fully and as quickly as possible and especially to removethe accumulation of plaque, mucilaginous and bacterial deposits whichcollect while the denture is being worn. To wear a denture which has notbeen completely cleaned of plaque and bacterial deposits is not onlyunhygenic but can also within a short space of time result in adetrimental effect on the mucous membrane. Moreover bacterial depositscan lead to so-called bacterial corrosion of the plastics material usedto produce the denture with consequent color-change andmalodor-formation.

It is known to include silicones in dentifrice compositions, allegedlyto coat the teeth and prevent cavities and staining. For instance,GB-A-689,679 discloses a mouthwash containing an organopolysiloxane forpreventing adhesion of, or for removing tars, stains, tartar and foodparticles from the teeth.

U.S. Pat. No. 2,806,814 discloses dental preparations including, incombination, a higher aliphatic acyl amide of an amino carboxylic acidcompound as an active and a silicone compound. The patent notes thatsilicone compounds have been proposed for prevention of adhesion or tofacilitate the removal of tars, stains, tartar and the like from teeth.The silicone compound is said to act as a synergist in improving theantibacterial and acid inhibiting activity of the active ingredient.Dimethyl polysiloxanes are said to be particularly effective.

U.S. Pat. No. 3,624,120 discloses quaternary ammonium salts of cyclicsiloxane polymers for use as cationic surfactants, bactericides and asanticariogenic agents.

Dentures of course are generally made of a plastics material such asacrylic and the problem of preventing plaque accumulation or of removingplaque from dentures is therefore fundamentally different from theproblem of plaque prevention and removal from dental enamal.

Accordingly, the present invention provides a denture cleanser havingimproved efficacy on plaque, mucilaginous and bacterial deposits andwhich at the same time provides excellent denture cleansing performance,appearance, physical characteristics, dissolution and in-use performancecharacteristics.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided adenture cleansing composition comprising an inorganic persalt bleachingagent, an effervescence generator and an aminoalkylsilicone asantiplaque agent. The present invention also relates to the use of thedefined aminoalkylsilicone as antiplaque agent in denture cleansingcompositions

All percentages and ratios herein are by weight of total composition,unless otherwise indicated.

The cleansing compositions of the invention thus comprise threeessential components, a bleaching agent, an aminoalkylsilicone and aneffervescent base composition. Each of these will be discussed in turn.

The bleaching agent takes the form of an inorganic persalt and can beselected from any of the well-known bleaching agents known for use indenture cleansers such as the alkali metal and ammonium persulfates,perborates, percarbonates and perphosphates and the alkali metal andalkaline earth metal peroxides. Examples of suitable bleaching agentsinclude potassium, ammonium, sodium and lithium persulfates andperborate mono- and tetrahydrates, sodium pyrophosphate peroxyhydrateand magnesium, calcium, strontium and zinc peroxides. Of these, however,the alkali metal persulfates, perborates and mixtures thereof areprefered for use herein, highly preferred being the alkali metalperborates. Indeed, it is a feature of the invention that the tabletcompositions herein will provide excellent antimicrobial activity evenin the absence of alkali metal persulfates.

The amount of bleaching agent in the total composition is generally fromabout 5 to about 70% preferably from about 10% to about 50%. Incompositions comprising a mixture of alkali metal persulfates andperborates, the overall persulfate:perborate ratio is suitably fromabout 5:1 to about 1:5, more especially from about 2:1 to about 1:2.

The compositions herein also contain an aminoalkylsilicone antiplaqueagent. In general terms, the aminoalkylsilicone is selected fromnoncyclic, hydrophobic aminoalkysilicones having a formula comprisingtwo basic units:

1) (R¹)_(m) (R)_(n) SiO.sub.(4-m-n)/2 wherein m+n is 1, 2 or 3; n is 1,2 or 3; mis 0,1,2; and

2) (R¹)_(a) (R²)_(b) SiO.sub.(4-a-b)/2 wherein a+b is 1, 2, or 3, and aand b are integers,

wherein R¹ and R² are independently selected from H ,alkyl and alkenylof about 1 to about 10 carbons optionally substituted with fluoro orcyano groups, hydroxy, alkoxy, and acetoxy, for example, wherein R¹ andR² are independently selected from methyl, ethyl, phenyl, vinyl,trifluoropropyl and cyanopropyl, and R is ##STR1## wherein R³ is adivalent alkylene of about 1-20, preferably about 3-5 carbon atomsoptionally substituted or interrupted by O atoms, R⁴, R⁵ and R⁶ whichmay be the same or different are selected from H, alkyl of about 1-20,preferably about 1-10, more preferably about 1-4 carbons optionallysubstituted or interrupted by N and/or O atoms, and X is a monovalentanion such as halide, hydroxide, and tosylate, said aminoalkylsiliconeincluding about 60% or less, preferably from about 0.1-30%, morepreferably from 0.2-10% and especially from about 0.5-2% of unit (1) ona repeating unit basis.

In a preferred embodiment, the aminoalkylsilicones compriseamodimethicones. Amodimethicones are polydimethylsiloxane polymerscontaining aminoalkyl groups. The aminoalkyl groups may be presenteither pendant or at one or more ends of the polydimethylsiloxane chain.Preferred are aminoalkylsilicones in which aminoalkyl moiety R isselected from (CH₂)₃ NH₂, (CH₂)₃ NHCH₂ CH₂ NH₂, (CH₂)₃ N(CH₂ CH₂ OH)₂,(CH₂)₃ NH₃ ⁺ X⁻, and (CH₂)₃ N(CH₃)₂ (C₁₈ H₃₇)⁺ X⁻, and especially from(CH₂)₃ NH₂ and (CH₂)₃ NHCH₂ CH₂ NH₂. Also preferred are aminoalkylsilicones having an average molecular weight of about 5,000 and above,preferably from about 5000 to about 100,000, more preferably from about5000 to about 30,000.

Aminoalkylsilicone compounds suitable for use herein are well known.Methods of preparing aminoalkylsilicones are given in, for example, U.S.Pat. No. 2,930,809.

Examples of amodimethicones include Dow Corning's DC-929, DC-Q2-7224 andQ2-8075 and OSI's Magnasoft fluid, the latter being preferred. Thesepolymers comprise aminoalkyl groups affixed to a predominantlypolydimethylsiloxane structure. The typical structure of Magnasoft'saminoalkyl group-containing units is

    --OSi(Me)C.sub.3 H.sub.6 NHCH.sub.2 CH.sub.2 NH.sub.2.

The aminoalkylsilicone is generally present in a level of from about0.01% to about 25%, preferably from about 0.1% to about 5%, morepreferably from about 0.5% to about 1.5% by weight.

The denture cleansing compositions also incorporate an effervescencegenerator which in preferred embodiments takes the form of a solid basematerial which in the presence of water releases carbon dioxide oroxygen with effervescence. The effervescence generator utilized in thecompositions herein can be selected from generators which are effectiveunder acid, neutral or alkaline pH conditions, but preferably itconsists of a combination of a generator which is effective or mosteffective under acid or neutral pH conditions and a generator which iseffective or most effective under alkaline pH conditions. Effervescencegenerators which are effective under acid or neutral pH conditionsinclude a combination of at least one alkali metal carbonate orbicarbonate, such as sodium bicarbonate, sodium carbonate, sodiumsesquicarbonate, potassium carbonate, potassium bicarbonate, or mixturesthereof, in admixture with at least one non-toxic,physiologically-acceptable organic acid, such as tartaric, fumaric,citric, malic, maleic, gluconic, succinic, salicylic, adipic orsulphamic acid, sodium fumarate, sodium or potassium acid phosphates,betaine hydrochloride or mixtures thereof. Of these, malic acid ispreferred. Effervescence generators which are effective under alkalinepH conditions include persalts such as alkali and alkaline earth metalperoxoborates as well as perborates, persulphates, percarbonates,perphosphates and mixtures thereof as previously described, for example,a mixture of an alkali metal perborate (anhydrous, mono- ortetrahydrate) with a monopersulphate such as Caroat ^(R) marketed by E Idu Point de Nemours Co. and which is a 2:1:1 mixture of monopersulphate,potassium sulphate and potassium bisulphate and which has an activeoxygen content of about 4.5%.

In highly preferred compositions, the solid base material incorporates a(bi)carbonate/acid effervescent couple optionally in combination with aperborate/persulphate oxygen effervescence generator. The combination ofgenerators is valuable for achieving optimum dissolution characteristicsand pH conditions for achieving optimum cleaning and antimicrobialactivity. The (bi)carbonate components generally comprise from about 5%to about 65%, preferably from about 25% to 55% of the total composition;the acid components generally comprise from about 5% to about 50%,preferably from about 10% to about 30% of the total composition.

The compositions of the invention can be supplemented by other knowncomponents of denture cleansing formulations. An especially preferredadditional component is an organic peroxyacid precursor, which ingeneral terms can be defined as a compound having a titre of at least1.5 ml of 0.1 N sodium thiosulfate in the following peracid formationtest.

A test solution is prepared by dissolving the following materials in1000 mls distilled water:

    ______________________________________                                        sodium pyrophosphate     2.5 g                                                (Na.sub.4 P.sub.2 O.sub.7.10H.sub.2 O)                                        sodium perborate        0.615 g                                               (NaBO.sub.2.H.sub.2 O.sub.2.3H.sub.2 O) having                                10.4% available oxygen                                                        sodium dodecylbenzene    0.5 g                                                sulphonate                                                                    ______________________________________                                    

To this solution at 60° C. an amount of activator is added such that foreach atom of available oxygen present one molecular equivalent ofactivator is introduced.

The mixture obtained by addition of the activator is vigorously stirredand maintained at 60° C. After 5 minutes from addition, a 100 ml portionof the solution is withdrawn and immediately pipetted onto a mixture of250 g cracked ice and 15 ml glacial acetic acid. Potassium iodide (0.4g) is then added and the liberated iodine is immediately titrated with0.1 N sodium thiosulphate with starch as indicator until the firstdisappearance of the blue colour. The amount of sodium thiosulphatesolution used in ml is the titre of the bleach activator.

The organic peracid precursors are typically compounds containing one ormore acyl groups, which are susceptible to perhydrolysis. The preferredactivators are those of the N-acyl or O-acyl compound type containing aacyl radical R--CO wherein R is a hydrocarbon or substituted hydrocarbongroup having preferably from about 1 to about 20 carbon atoms. Examplesof suitable peracid precursors include:

1) Acyl organoamides of the formula RCONR₁ R₂, where RCO is carboxylicacyl radical, R₁ is an acyl radical and R₂ is an organic radical, asdisclosed in U.S. Pat. No. 3,117,148. Examples of compounds fallingunder this group include:

a) N,N-diacetylaniline and N-acetylphthalimide;

b) N-acylhydantoins, such as N,N'-diacetyl-5,5-dimethylhydantoin;

c) Polyacylated alkylene diamines, such asN,N,N'N'-tetraacetylethylenediamine (TAED) and the correspondinghexamethylenediamine (TAHD) derivatives, as disclosed in GB-A-907,356,GB-A-907,357 and GB-A-907,358;

d) Acylated glycolurils, such as tetraacetylglycoluril, as disclosed inGB-A-1,246,338, GB-A-1,246,339 and GB-A-1,247,429.

2) Acylated sulphonamides, such as N-methyl-N-benzoyl-menthanesulphonamide and N-phenyl-N-acetyl menthane sulphonamide, as disclosedin GB-A-3,183,266.

3) Carboxylic esters as disclosed in GB-A-836,988, GB-A-963,135 andGB-A-1,147,871. Examples of compounds of this type include phenylacetate, sodium acetoxy benzene sulphonate, trichloroethylacetate,sorbitol hexaacetate, fructose pentaacetate, p-nitrobenzaldehydediacetate, isopropeneyl acetate, acetyl aceto hydroxamic acid, andacetyl salicylic acid. Other examples are esters of a phenol orsubstituted phenol with an alpha-chlorinated lower aliphatic carboxylicacid, such as chloroacetylphenol and chloroacetylsalicylic acid, asdisclosed in U.S. Pat. No. 3,130,165.

4) Carboxylic esters having the gernal formal Ac L wherein Ac is theacyl moiety of an organic carboxylic acid comprising an optionallysubstituted, linear or branched C₆ -C₂₀ alkyl or alkenyl moiety or a C₆-C₂₀ alkyl-substituted aryl moiety and L is a leaving group, theconjugate acid of which has a pKa in the range from 4 to 13, for exampleoxybenzenesulfonate or oxybenzoate. Preferred compounds of this type arethose wherein:

a) Ac is R₃ --CO and R₃ is a linear or branched alkyl group containingfrom 6 to 20, preferably 6 to 12, more preferably 7 to 9 carbon atomsand wherein the longest linear alkyl chain extending from and includingthe carbonyl carbon contains from 5 to 18, preferably 5 to 10 carbonatoms, R₃ optionally being substituted (preferably alpha to the carbonylmoiety) by Cl, Br, OCH3 or OC₂ H₅. Examples of this class of materialinclude sodium 3,5,5-trimethylhexanoyloxybenzene sulfonate, sodium3,5,5-trimethylhexanoyloxybenzoate, sodium 2-ethylhexanoyloxybenzenesulfonate, sodium nonanoyl oxybenzene sulfonate and sodiumoctanoyl oxybenezenesulfonate, the acyloxy group in each instancepreferably being p-substituted;

b) Ac has the formula R₃ (AO)_(m) XA wherein R₃ is a linear or branchedalkyl or alkylaryl group containing from 6 to 20, preferably from 6 to15 carbon atoms in the alkyl moiety, R₅ being optionally substituted byCl, Br, OCH₃, or OC₂ H₅, AO is oxyethylene or oxypropylene, m is from 0to 100, X is O, NR₄ or CO--NR₄, and A is CO, CO--CO, R₆ --CO, CO--R₆--CO, or CO--NR₄ --R₆ --CO wherein R₄ is C₁ -C₄ alkyl and R₆ isalkylene, alkenylene, arylene or alkarylene containing from 1 to 8carbon atoms in the alkylene or alkenylene moiety. Bleach activatorcompounds of this type include carbonic acid derivatives of the formulaR₃ (AO)_(m) OCOL, succinic acid derivatives of the formula R₃ OCO(CH₂)₂COL, glycollic acid derivatives of the formula R₃ OCH₂ COL,hydroxypropionic acid derivatives of the formula R₃ OCH₂ CH₂ COL, oxalicacid derivatives of the formula R₃ OCOCOL, maleic and fumaric acidderivatives of the formula R₃ OCOCH═CHCOL, acyl aminocaproic acidderivatives of the formula R₃ CONR₁ (CH₂)₆ COL, acyl glycine derivativesof the formula R₃ CONR₁ CH₂ COL, and amino-6-oxocaproic acid derivativesof the formula R₃ N(R₁)CO(CH₂)₄ COL. In the above, m is preferably from0 to 10, and R₃ is preferably C₆ -C₁₂, more preferably C₆ -C₁₀ alkylwhen m is zero and C₉ -C₁₅ when m is non-zero. The leaving group L is asdefined above.

5) Acyl-cyanurates, such as triacetyl- or tribenzoylcyanurates, asdisclosed in US patent specification No. 3,332,882.

6) Optionally substituted anhydrides of benzoic or phthalic acid, forexample, benzoic anhydride, m-chlorobenzoic anhydride and phthalicanhydride.

Of all the above, preferred are organic peracid precursors of types 1(c)and 4(a).

Where present, the level of peroxyacid bleach precursor by weight of thetotal composition is preferably from about 0.1% to about 10%, morepreferably from about 0.5% to about 5% and is generally added in theform of a bleach precursor agglomerate.

The bleach precursor agglomerates preferred for use herein generallycomprise a binder or agglomerating agent in a level of from about 5% toabout 40%, more especially from about 10% to about 30% by weightthereof. Suitable agglomerating agents include polyvinylpyrrolidone,poly (oxyethylene) of molecular weight 20,000 to 500,000,polyethyleneglycols of molecular weight of from about 1000 to about50,000, Carbowax having a molecular weight of from 4000 to 20,000,nonionic surfactants, fatty acids, sodium carboxymethyl cellulose,gelatin, fatty alcohols, phosphates and polyphosphates, clays,aluminosilicates and polymeric polycarboxylates. Of the above,polyethyleneglycols are highly preferred, especially those havingmolecular weight of from about 1,000 to about 30,000, preferably 2000 toabout 10,000.

Preferred from the viewpoint of optimum dissolution and pHcharacteristics are bleach precursor agglomerates which comprise fromabout 10% to about 75%, preferably from about 20% to about 60% by weightthereof of peroxyacid bleach precursor, from about 5% to about 60%preferably from about 5% to about 50%, more preferably from about 10% toabout 40% of a (bi) carbonate/acid effervescent couple, from about 0% toabout 20% of a peroxoboroate, and from about 5% to about 40%, preferablyfrom about 10% to about 30% of an agglomerating agent.

The final bleach precursor granules desirably have an average particlesize of from about 500 to about 1500, preferably from about 500 to about1,000 μm, this being valuable from the viewpoint of optimum dissolutionperformance and aesthetics. The level of bleach precursor agglomerates,moreover, is preferably from about 1% to about 20%, more preferably fromabout 5% to about 15% by weight of composition.

The compositions of the invention can be in paste, liquid, tablet,granular or powder form, although tablet-form compositions are highlypreferred herein. Compositions in tablet form can be single or multiplelayered tablets.

The compositions of the invention can be supplemented by other usualcomponents of denture cleansing formulations, especially surfactants,chelating agents, enzymes, flavorants, physiological cooling agents,antimicrobial compounds, dyestuffs, sweeteners, tablet binders andfillers, foam depressants such as dimethylpolysiloxanes, foamstabilizers such as the fatty acid sugar esters, preservatives,lubricants such as talc, magnesium stearate, finely divided amorphouspyrogenic silicas, etc. The free moisture content of the finalcomposition is desirably less than about 1% and especially less thanabout 0.5%.

Tablet binders and fillers suitable for use herein includepolyvinylpyrrolidone, poly (oxyethylene) of molecular weight 20,000 to500,000, polyethyleneglycols of molecular weight of from about 1000 toabout 50,000, Carbowax having a molecular weight of from 4000 to 20,000,nonionic surfactants, fatty acids, sodium carboxymethyl cellulose,gelatin, fatty alcohols, clays, polymeric polycarboxylates, sodiumcarbonate, calcium carbonate, calcium hydroxide, magnesium oxide,magnesium hydroxide carbonate, sodium sulfate, proteins, celluloseethers, cellulose esters, polyvinyl alcohol, alginic acid esters,vegetable fatty materials of a pseudocolloidal character. Of the above,polyethyleneglycols are highly preferred, especially those havingmolecular weight of from about 1,000 to about 30,000, preferably fromabout 12,000 to about 30,000.

The surface active agent used in the compositions of the invention canbe selected from the many available that are compatible with the otheringredients of the denture cleanser, both in the dry state and insolution. Such materials are believed to improve the effectiveness ofthe other ingredients of the composition by aiding their penetrationinto the interdental surfaces. Also, these materials aid in the removalof food debris attached to the teeth. Between 0.1 and 5 percent byweight of the dry composition of a dry powder or granular anionicsurface active agent, such as sodium lauryl sulfate, sodiumN-lauroylsarcosinate, sodium lauryl sulfoacetate or dioctyl sodiumsulfosuccinate or ricinoleyl sodium sulfosuccinate, may, for example, beincluded in the composition and preferably the surface active agentcomprises between 0.5 and 4 percent of the composition.

Suitable cationic, non-ionic and ampholytic surface active agentsinclude, for example, quaternary ammonium compounds such ascetyltrimethylammonium bromide, condensation products of alkylene oxidessuch as ethylene or propylene oxide with fatty alcohols, phenols, fattyamines or fatty acid alkanolamides, the fatty acid alkanolamidesthemselves, esters of long-chained (C₈ -C₂₂) fatty acids withpolyalcohols or sugars, for example glycerylmonostearate orsaccharosemonolaurate or sorbitolpolyoxyethylenemono-or di-stearate,betaines, sulphobetaines or long-chain alkylaminocarboxylic acids.

Chelating agents beneficially aid cleaning and bleach stability bykeeping metal ions, such as calcium, magnesium, and heavy metal cationsin solution. Examples of suitable chelating agents include sodiumtripolyphosphate, sodium acid pyrophosphate, tetrasodium pyrophosphate,aminopolycarboxylates such as nitrilotriacetic acid and ethylenediaminetetracetic acid and salts thereof, and polyphosphonates andaminopolyphosphonates such as hydroxyethanediphosphonic acid,ethylenediamine tetramethylenephosphonic acid,diethylenetriaminepentamethylenephosphonic acid and salts thereof. Thechelating agent selected is not critical except that it must becompatible with the other ingredients of the denture cleanser when inthe dry state and in aqueous solution. Advantageously, the chelatingagent comprises between 0.1 and 60 percent by weight of the compositionand preferably between 0.5 and 30 percent. Phosphonic acid chelatingagents, however, preferably comprise from about 0.1 to about 1 percent,preferably from about 0.1% to about 0.5% by weight of composition.

Enzymes suitable for use herein are exemplified by proteases, alkalases,amylases, lipases, dextranases, mutanases, glucanases etc.

Flavorants suitable for use in the compositions of the invention includewintergreen oil, oregano oil, bay leaf oil, peppermint oil, spearmintoil, clove oil, sage oil, sassafras oil, lemon oil, orange oil, aniseoil, benzaldehyde, bitter almond oil, camphor, cedar leaf oil, marjoramoil, citronella oil, lavendar oil, mustard oil, pine oil, pine needleoil, rosemary oil, thyme oil, cinnamon leaf oil, and mixtures thereof.Suitable antimicrobial compounds include thymol, menthol, triclosan,4-hexylresorcinol, phenol, eucalyptol, benzoic acid, benzoyl peroxide,butyl paraben, methyl paraben, propyl paraben, salicylamides, andmixtures thereof.

The following Examples further describe and demonstrate the preferredembodiments within the scope of the present invention.

EXAMPLES I TO V

The following are representative denture cleansing tablets according tothe invention. The percentages are by weight of the total tablet. Thetablets are made by compressing a mixture of the granulated componentsin a punch and dye tabletting press at a pressure of about 10⁵ kPa.

    ______________________________________                                                   I     II      III     IV    V                                      ______________________________________                                        Malic Acid   12      10      15    --    14                                   Citric Acid  --      10      --    15    --                                   Sodium Carbonate                                                                           10       8      10     6    10                                   Sulphamic Acid                                                                              5      --      --     3     3                                   PEG 20,000   --       3       7     8     5                                   PVP 40,000    6       3      --    --    --                                   Sodium Bicarbonate                                                                         22      19        24.5                                                                              13    23                                   Sodium Perborate                                                                           15      12      16    30    15                                   Monohydrate                                                                   Potassium    15      18      13    --    14                                   Monopersulphate                                                               Pyrogenic Silica                                                                           --       3       1     1    --                                   Talc          2      --      --    --    --                                   EDTA         --      --       1    --     3                                   EDTMP.sup.1   1      --      --     1    --                                   Flavor.sup.5  2       1       2     1     2                                   Magnasoft Fluid.sup.4                                                                       1       5        0.5 10     1                                   Bleach Precursor                                                                            9       8      10    12    10                                   Agglomerate                                                                   Bleach Precursor                                                              Agglomerate                                                                   TAED.sup.2    2      --       4     5      2.5                                TMHOS.sup.3   2       3      --    --    --                                   Sulphamic Acid                                                                              2       2       2     2      3.5                                Sodium Bicarbonate                                                                           0.5     0.2     0.2   0.5  2                                   PEG 6000       2.5    2        2.4   2.5   1.5                                Dye          --        0.8     1.4  2      0.5                                ______________________________________                                         .sup.1 Ethylenediaminetetramethylenephosphonic acid                           .sup.2 Tetraacetylethylene diamine                                            .sup.3 Sodium 3,5,5trimethylhexanoyloxybenzene sulfonate                      .sup.4 Magnasoft Fluid                                                        .sup.5 Peppermintbased flavor                                            

In Examples I to V above, the overall tablet weight is 3 g; diameter 25mm.

The denture cleansing tablets of Examples I to V display improvedantiplaque efficacy together with excellent cleansing and anti-bacterialactivity, cohesion and other physical and in-use performancecharacteristics.

We claim:
 1. A denture cleansing composition comprising an inorganicpersalt bleaching agent, an effervescence generator an organicperoxyacid bleach precursor and an aminoalkyl silicone wherein theaminoalkylsilicone is a noncyclic hydrophobic aminoalkylsilicone havinga formula comprising two basic units:1) (R¹)_(m) (R)_(n)SiO.sub.(4-m-n)/2 wherein m+n is 1, 2 or 3; n is 1,2 or 3; m is0,1,2;and 2) R¹)_(a) (R²)_(b) SiO.sub.(4-a-b)/2 wherein a+b is 1, 2, or3, and a and b are integers,wherein R¹ and R² are independently selectedfrom H, alkyl and alkenyl of about optionally substituted with fluoro orcyano groups, hydroxy, alkoxy, and acetoxy, and R is ##STR2## wherein R³is a divalent alkylene of about 1-20 carbon atoms optionally substitutedor interrupted by O atoms, R⁴, R⁵ and R⁶ which may be the same ordifferent are selected from H, alkyl of about 1-20 carbons optionallysubstituted or interrupted by N and/or O atoms, and X⁻ is a monovalentanion, said aminoalkyl silicone including about 60% or less of unit (1)on a repeating unit basis.
 2. A composition according to claim 1 whereinthe aminoalkyl silicone has a molecular weight of at least about 5,000,.3. A composition according to claim 2 wherein R¹ and R² areindependently selected from methyl, ethyl, phenyl, vinyl,trifluoropropyl and cyanopropyl.
 4. A composition according to claim 3wherein R³ is a divalent alkylene having from 3 to 5 carbon atoms.
 5. Acomposition according to claim 4 wherein R is selected from (CH₂)₃ NH₂,(CH₂)₃ NHCH₂ CH₂ NH₂, (CH₂)₃ N(CH₂ CH₂ OH)₂, (CH₂)₃ NH₃ ⁺ X⁻, and (CH₂)₃N(CH₃)₂ (C₁₈ H₃₇)⁺ X⁻.
 6. A composition according to claim 5 wherein theaminoalkylsilicone is amodimethicone.
 7. A composition according toclaim 6 comprising from about 0.01% to about 25%, by weight of theaminoalkylsilicone.
 8. A composition according to claim 7 wherein theinorganic persalt bleaching agent comprises one or more bleaching agentsselected from alkali metal persulfates, alkali metal perborates andmixtures thereof.
 9. A composition according to claim 7 wherein theeffervescence generator comprises a (bi)carbonate/acid effervescentcouple.
 10. A composition according to claim 1 wherein the organicperoxyacid bleach precursor is selected from acylated polyalkyldiamines,especially tetraacetylethylenediamine, and carboxylic esters having thegeneral formula AcL wherein Ac is the acyl moiety or an organiccarboxylic acid comprising an optionally substituted, linear or branchedC₆ -C₂₀ alkyl or alkenyl moiety or a C₆ -C₂₀ alkyl-substituted arylmoiety and L is a leaving group, the conjugate acid of which has a pKain the range from 4 to
 13. 11. A composition according to claim 2wherein the aminoalkyl silicone has a molecular weight of at least fromabout 5000 to about 100,000.
 12. A composition according to claim 8comprising from about 0.1% to about 5% by weight of theaminoalkylsilicone.
 13. A method of cleaning dentures by applying to thedentures, a composition comprising an inorganic persalt bleaching agent,an effervescence generator an organic peroxyacid bleach precursor and anaminoalkylsilicone wherein the aminoalkylsilicone is a noncyclic,hydrophobic aminoalkylsilicone having a formula comprising two basicunits:1) (R¹)_(m) (R)_(n) SiO.sub.(4-m-n)/2 wherein m+n is 1, 2 or 3; nis 1, 2 or 3; m is0,1,2;and 2) (R¹)_(a) (R²)_(b) SiO.sub.(4-a-b)/2wherein a+b is 1, 2, or 3, and a and b are integers,wherein R¹ and R²are independently selected from H, and alkenyl of about 1 to about 10carbons optionally substituted with fluoro or cyano groups, hydroxy,alkoxy, and acetoxy, and R is ##STR3## wherein R³ is a divalent alkyleneof about 1-20 carbon atoms optionally substituted or interrupted by Oatoms, R⁴, R⁵ and R⁶ which may be the same or different are selectedfrom H, alkyl of about 1-20 carbons optionally substituted orinterrupted by N and/or O atoms, and X is a monovalent anion, saidaminoalkyl silicone including about 60% or less of unit (1)-on arepeating unit basis.